Composition

ABSTRACT

An aqueous shear-thinning personal care composition comprising: 
     (a) at least 3 wt % of a sulfonate compound of general formula 
     
       
         
         
             
             
         
       
     
     where R 1  represents a C 8-22  alkyl group alkyl group; R 2  represents a C 1-4  alkyl group; each of R 3 , R 4  and R 5  independently represents a hydrogen atom or a C 1-4  alkyl group; and M +  represents a sodium or potassium cation;
 
(b) at least 3 wt % of an amphoteric or zwitterionic surfactant;
 
(c) at least 10 wt % of water; and
 
(d) at least 0.5 wt % of an additional component in the form of particles or droplets suspended in the composition. The composition is stable in an aqueous environment and can be formulated with a wide range of additional components.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation application of co-pending patent application Ser.No. 15/154,129, filed May 13, 2016, which was a continuation of U.S.application Ser. No. 12/742,834, filed Jun. 4, 2010, which was a 371 ofinternational patent application PCT/GB2008/051071, filed Nov. 17, 2008,which claimed priority to British patent application 07225550.1, filedNov. 16, 2007. Each of these applications is hereby incorporated hereinby reference in its entirety.

BACKGROUND AND SUMMARY

This invention relates to a personal care composition, for example aliquid or gel body wash, shower gel, handwash, skin cream, hairconditioner or moisturiser.

U.S. Pat. No. 5,612,307 discloses an aqueous liquid cleansing andmoisturising composition comprising: a) a surface active agent selectedfrom anionic, nonionic, zwitterionic and cationic, surface activeagents, soap and mixtures thereof; and b) a benefit agent;

wherein the benefit agent and surface active agent are separate butcombinedly dispensable from a single packaging means in a predeterminedratio as discrete domains, the domains having one dimension of at leastabout 1000 microns.

An advantage of the invention of U.S. Pat. No. 5,612,307 is said to bethat it leads to improved deposition of benefit agents from a surfaceactive agent containing aqueous liquid composition during use. Thesurface active agent and benefit agent are separated in the composition,i.e. they do not directly contact one another in the composition. Thisavoids adverse interactions which may occur between these two componentsand which may result in ineffective deposition of the benefit agent.

The composition of U.S. Pat. No. 5,612,307 is said to be suitable forcleansing and “moisturising”, “conditioning” or “protection” of theskin. The benefit agent is included in the composition to moisturise,condition and/or protect the skin. By “benefit agent” is meant asubstance that softens the skin (stratum corneum) and keeps it soft byretarding the decrease of its water content and/or protects the skin.

Preferred benefit agents of U.S. Pat. No. 5,612,307 include: siliconesand siloxanes; fats and oils; waxes; hydrocarbons; higher fatty acids;higher alcohols; esters; essential oils; lipids; vitamins; sunscreens;and phospholipids.

Where adverse interactions between the benefit agent and surface activeare likely to be particularly acute, U.S. Pat. No. 5,612,307 states thatthe benefit agent may be incorporated in the compositions in a carrier.

The surface active agent of U.S. Pat. No. 5,612,307 is preferablypresent at a level of from 1 to 35 wt %, preferably 3 to 30 wt %.

One preferred anionic detergent for use in the invention of U.S. Pat.No. 5,612,307 is a fatty acyl ethane sulfonate of formulaRCO₂CH₂CH₂SO₃M, where R is an alkyl or alkenyl group of 7 to 21 carbonatoms and M is a solubilising cation such as sodium, potassium, ammoniumor substituted ammonium. Preferably at least three quarters of the RCOgroups have 12 to 18 carbon atoms and may be derived from coconut, palmor a coconut/palm blend.

It is also preferable in U.S. Pat. No. 5,612,307 that the compositionincludes from 0.5 to 15 wt % of a cosurfactant agent with skin-mildnessbenefits. Suitable materials are zwitterionic detergents identified inU.S. Pat. No. 5,612,307.

A favoured fatty acyl ethane sulfonate is “SCI” (sodium cocylisethionate). SCI is commercially available and is a successful productbut the scope it offers formulators is limited by its low solubility inwater; its low hydrolytic stability, and the lack of stability in its pHvalue, over time.

The present invention is based on the use of a different fatty acylsulfonate salt, and its advantageous co-formulation with amphoteric orzwitterionic surfactants, in aqueous environments.

In accordance with a first aspect of the present invention there isprovided an aqueous shear-thinning personal care composition comprising:

(a) at least 3 wt % of a sulfonate compound of general formula

where R¹ represents a C₈₋₂₂ alkyl group;R² represents a C₁₋₄ alkyl group;each of R³, R⁴ and R⁵ independently represents a hydrogen atom or a C₁₋₄alkyl group; andM⁺ represents a cation;(b) at least 3 wt % of an amphoteric or zwitterionic surfactant;(c) at least 10 wt % of water; and(d) at least 0.5 wt % of an additional component in the form ofparticles or droplets suspended in the composition.

There may be further components present in the composition. Percentagesgiven herein are percentages on total weight of the composition,including any such further components, for example when there is aplurality of compounds (a); and/or a plurality of surfactants (b).

Many additional components are described hereafter, some of which may gointo solution and some of which remain in the composition as particlesor droplets. The stipulation of the definition of the invention is thatthere must be at least one additional component which is in the form ofparticles or droplets suspended in the composition. The compositions ofthe present invention have an exceptional ability to be formulated withfurther components and in particular to suspend particles or dropletsand we regard this as an essential element of the invention.

Preferably R¹ represents a C₁₀₋₂₀ alkyl group, most preferably a C₁₂₋₁₈alkyl group.

Preferably R² represents a C₁₋₄ alkyl group in which a propyl or butylgroup is straight-chain. Preferably R² represents an n-propyl, ethyl or,most preferably, a methyl group.

Preferably R³ represents a hydrogen atom.

Preferably one of R⁴ and R⁵ represents a hydrogen atom and the otherrepresents a hydrogen atom or a C₁₋₄ alkyl group, Preferably one of R⁴and R⁵ represents a hydrogen atom or a C₁₋₄ alkyl group in which apropyl or butyl group is straight-chain. Preferably one of R⁴ and R⁵represents an n-propyl, ethyl or methyl group or, most preferably, ahydrogen atom. Most preferably both R⁴ and R⁵ represent hydrogen atoms.

Preferably M⁺ represents an ammonium cation or, most preferably, a metalcation. Suitable metal cations include alkali metal cations, for examplesodium and potassium cations, and alkaline earth metal cations, forexample calcium and magnesium cations. Preferably M⁺ represents apotassium cation, or, especially, a sodium cation.

Of course, a plurality of compounds (a) may be present.

Component (b) may include amphoteric or zwitterionic surfactantsselected from betaines, for example alkyl betaines, alkylamidopropylbetaines, alkyamidopropyl hydroxysultaines, alkylampho acetates,alkylamphodi-acetates, alkylamphopropionates, alkylamphodipropionates,alkyliminodipropionates and alkyliminodiacetate.

Of course, a plurality of surfactants (b) may be present.

Amphoteric or zwitterionic surfactants may include those which have analkyl or alkenyl group of 7 to 22 carbon atoms and comply with anoverall structural formula:

where R¹ is alkyl or alkenyl of 7 to 22 carbon atoms; R² and R³ are eachindependently alkyl, hydroxyalkyl or carboxyalkyl of 1 to 6 carbonatoms; m is 2 to 4; n is 0 or 1; X is alkylene of 1 to 6 carbon atomsoptionally substituted with hydroxyl; and Y is —CO₂ or —SO₃.

Amphoteric or zwitterionic surfactants may include simple betaines offormula:

and amido betaines of formula:

where m is 2 or 3.

In both formulae R¹, R² and R³ are as defined previously. R¹ may, inparticular, be a mixture of C₁₂ and C₁₄ alkyl groups derived fromcoconut so that at least half, preferably at least three quarters, ofthe groups R¹ has 10 to 14 carbon atoms. R² and R³ are preferablymethyl.

Amphoteric or zwitterionic surfactants may include sulphobetaines offormula:

where m is 2 or 3, or variants of these in which —(CH₂)₃SO₃ ⁻ isreplaced by

where R¹, R² and R³ in these formulae are as defined previously.

Amphoteric or zwitterionic surfactants may include amphoacetates anddiamphoacetates. Amphoacetates generally conform to the followingformula:

Diamphoacetates generally conform to the following formula:

where R is an aliphatic group of 8 to 22 carbon atoms and M is a cationsuch as sodium, potassium, ammonium, or substituted ammonium.

Compounds such as oleylbetaine and cocoamidopropylhydroxy-sultaine areregarded as very safe for the human body and for the eyes. Alsopreferred in some embodiments are sodium lauroamphoacetate, sodiumcocoamphoactetate, disodium lauroamphoacetate, and disodiumcocoampho-diacetate.

Preferably, in a composition in accordance with the present invention,component (a) is present in an amount of up to 30% by total compositionweight.

Preferably in a composition in accordance with the present invention,component (b) is present in an amount of up to 30% by total compositionweight.

Preferably in a composition in accordance with the present invention,component (c) is present in an amount of from 20% to 95% by totalcomposition weight, preferably from 50 to 90%.

In one embodiment the composition of the present invention is afree-flowing liquid.

In one embodiment a composition in accordance with the invention is ashear thinning composition.

A composition in accordance with the present invention may suitably havea viscosity of from 250 to 300,000 mPa·s, measured at 25° C. using aBrookfield rotational viscometer equipped with an appropriate spindle ata rotation speed of from 0.1 revolutions per minute (rpm) to about 60rpm. Examples of appropriate spindles include the Brookfield RVTViscometer Helipath T-Bar Spindles B and C (used in the examples whichfollow). At low shear rates (rotation speeds) the viscosity as measuredmay be up to 300,000 mPa·s. At high shear rates (rotation speeds) theviscosity as measured may be as low as 250 mPa·s.

The compositions of the invention may be pourable liquids orsemi-liquids e.g.

The compositions of the invention may be soft gels and may suitably beof viscosity in the range 800 to 20,000 mPa·s, measured under theconditions stated above.

The compositions of the invention may be firmer gels and may be ofviscosity in the range 3000 to 100,000 mPa·s, measured under theconditions stated above.

Surprisingly, the aqueous compositions of the invention have desirablenon-Newtonian properties and excellent suspending properties, beingcapable of maintaining solid or non-solid water-insoluble particles ordroplets in suspension. Under the conditions of testing which have beenapplied in relation to the invention, no sedimentation or separationwhatsoever of the water-insoluble particles or droplets has developedover time. Furthermore the compositions of the invention produce anexcellent rich creamy foam which is stable, and is mild to the skin andeyes.

Without being bound by theory, it is believed possible that thefollowing microstructural conditions are achieved in the presentinvention.

The compositions of the present invention are believed to exhibit aso-called lamellar phase structure comprising spherulites in suspension.

By “lamellar phase” is intended a hydrated solid phase or a liquidcrystal phase in which several double layers are arranged in a parallelnetwork, separated by layers of water or of an aqueous solution. Inrespect of the spherulites, these are multilamellar vesicles comprisingseveral layers of surface-active agents arranged concentrically andgenerally ranging from 0.1 to 50 microns in size.

More specifically, the corresponding phase structure may, we believe, bea birefringent solution, optically characteristic of a non-isotropicmesomorphic phase. By the term “water-insoluble particles” are intendedsolid or non-solid entities which are not solubilized in the aqueousmedium of the subject composition. These, more particularly, are solidparticles or suspended droplets.

However the more significant point is not the microstructure per se butthe fact that the components together produce a composition withexcellent overall or macroscopic properties.

Important advantages of the compositions of the invention over manyother compositions, and in over particular over compositions containingfatty acyl ethane sulfonates, such as SCI, is that they arehydrolytically stable and pH-stable, and that they can be formulatedwith many further ingredients, including particulates and droplets,without adverse interactions being found.

The composition may contain an electrolyte. An electrolyte is suitablypresent in an amount of from 0.5% to 25%, preferably 1% to 15%,preferably 2 to 10%, by total composition weight. The concentrationthereof may be adjusted to produce the desired formulation.

Suitable as an electrolyte are ionic compounds, for example metal saltsselected from sodium chloride, sodium sulfate, potassium chloride,potassium sulfate, sodium phosphate, disodium phosphate, potassiumphosphate, dipotassium phosphate, sodium isethionate, sodium methylisethionate and sodium lactate; and non-metallic salts, for examplesodium citrate, ammonium chloride, ammonium citrate and ammoniumlactate.

Preferred electrolytes include sodium and ammonium chloride.

Said additional component (d) is suitably one or more benefit agents inthe form of particles or droplets. By “benefit agent” we can adopt thedefinition of US 2003/0180246A, that is, a “benefit agent” is any activeingredient that is to be delivered into the skin or hair, or onto theskin or hair, or both, at a desired location. For example, a benefitagent may be a substance that softens the skin (stratum corneum) andkeeps it soft by retarding the decrease of its water content; and/or asubstance which protects the skin; and/or an exfoliating material, forexample a water insoluble particulate or suspended abrasive.

Preferred benefit agents include:

-   -   a) silicone oils, gums and modifications thereof such as linear        and cyclic polydimethylsiloxanes, amino, alkyl alkylaryl and        aryl silicone oils;    -   b) fats and oils including natural fats and oils such as jojoba,        soyabean, rice bran, avocado, almond, olive, sesame, persic,        castor, coconut, mink oils; cacao fat, beef tallow, lard;        hardened oils obtained by hydrogenating the aforementioned oils;        and synthetic mono, di and triglycerides such as myristic acid        glyceride and 2-ethylhexanoic acid glyceride;    -   c) waxes such as carnauba, spermaceti, beeswax, lanolin and        derivatives thereof;    -   d) hydrophobic plant extracts;    -   e) hydrocarbons such as liquid paraffins, petroleum jelly,        microcrystalline wax, ceresin, squalene, squalane, and mineral        oil;    -   f) higher fatty acids such as lauric, myristic, palmitic,        stearic, behenic, oleic, linoleic linolenic, lanolic, isostearic        and poly unsaturated fatty acids (PUPA) acids;    -   g) higher alcohols such as lauryl, cetyl, steryl, oleyl,        behenyl, cholesterol and 2-hexadecanol alcohol;    -   h) esters (fatty acid esters, fatty alcohol esters) including        cetyl octanoate, myristyl lactate, cetyl lactate, isopropyl        myristate, myristyl myristate, isopropyl palmitate, isopropyl        adipate, butyl stearate, decyl oleate, cholesterol isostearate,        glycerol monostearate, glycerol distearate, glycerol        tristearate, alkyl lactate for example lauryl lactate, alkyl        citrate and alkyl tartrate;    -   i) essential oils such as fish oils, fragrance oils, mentha,        jasmine, camphor, white cedar, bitter orange peel, ryu,        turpentine, cinnamon, bergamont, citrus unshiu, calamus, pine,        lavender, bay, clove, hiba, eucalyptus, lemon, starflower,        thyme, peppermint, rose, sage, menthol, cineole, eugenol,        citral, citronelle, borneol, linalool, geraniol, evening        primrose, camphor, thymol, spirantol, pinene, limonene and        terpenoid oils;    -   j) lipids such as cholesterol, ceramides, sucrose esters and        pseudo-ceramides as described in European Patent Specification        No. 556 957;    -   k) vitamins such as vitamin A and E, and vitamin alkyl esters,        including those vitamin C alkyl esters;    -   l) sunscreens such as octyl methoxyl cinnamate (Parsol MCX) and        butyl methoxy benzoylmethane (Parsol 1789);    -   m) phospholipids; and    -   n) one or more of scrubbing beads, anti-dandruff agents, anti-UV        actives, mica, silica, pigments, natural and synthetic waxes,        zinc oxide, titanium dioxide.

Other examples of suitable benefit agents include: depigmentationagents; reflectants; UV absorbers, thickening agents; detangling/wetcombing agents; film forming polymers; humectants; amino acids and theirderivatives; antimicrobial agents; anti-acne agents; anti-aging agents;antiseptics; analgesics; local anesthetics; anti-hair loss agents; hairgrowth inhibitor agents; inflammation inhibitors; proteins; deodorantsand anti-perspirants; agents for treatment of dandruff, seborreheicdermatitis and psoriasis; skin emollients and skin moisturizers; hairconditioners; hair softeners; hair moisturizers; vitamins; tanningagents; skin lightening agents; antifungals such as antifungals for footpreparations; depilating agents; counterirritants; hemorrhoidals;insecticides; pigments or opacifying agents, moisturizing beads, naturalabrasives, synthetic abrasives such as polyoxyethylene beads, mineraloils, petrolatum, silicone oils, polyalkylsiloxanes,polyalkyarylsiloxanes, sunscreens, reflectants and the like; andmixtures thereof.

Examples of suitable reflectants include mica, alumina, calciumsilicate, glycol dioleate, glycol distearate, silica, sodium magnesiumfluorosilicate, and mixtures thereof.

Examples of suitable UV absorbers include benzophenone, bornelone, PABA(Para Amino Benzoic Acid), butyl PABA, cinnamidopropyl trimethylammonium chloride, disodium distyrylbiphenyl disulfonate, potassiummethoxycinnamate, and mixtures thereof.

The benefit agent (or benefit agents, in total) is preferably present inamount of from 0.1 to 50%, preferably from 1 to 40%, preferably from 1.5to 30%, and most preferably from 2 to 20% by weight based on thecomposition weight.

A structurant may be added to the phase comprising the surface activeagent, suitably in an amount of from 0.01%, preferably from 0.1%, morepreferably from 1%, by weight based on the composition weight.

A structurant may be added to the phase comprising the surface activeagent, suitably in an amount of up to 15%, preferably up to 12%, morepreferably up to 10%, and most preferably up to 5%, by weight based onthe composition weight.

The primary purpose of a structurant is to assist in the formation of alamellar phase. It is believed that a lamellar phase, if achieved, mayenable the compositions to suspend particles more readily while stillmaintaining good shear thinning properties. The lamellar phase alsoprovides consumers with desired rheology (“heaping”).

Suitable structurants include swelling clays, for example laponite;fatty acids and derivatives thereof, in particular, fatty acid esters;cross-linked polyacrylates such as Carbopol™ (polymers available fromGoodrich); acrylates and copolymers thereof; polyvinylpyrrolidone andcopolymers thereof; polyethylene imines; salts such as sodium chlorideand ammonium sulphate; sucrose esters; gellants; and mixtures thereof.Examples of fatty acids which may be used are C₁₀-C₂₂ acid (e.g. lauric,oleic etc.), isostearic acid, linoleic acid, linolenic acid, ricinoleicacid, elaidic acid, arichidonic acid, myristoleic acid and palmitoleicacid. Ester derivatives include propylene glycol isostearate, propyleneglycol oleate, glyceryl isostearate, glyceryl oleate and polyglyceryldiisostearate. Monoglyceride polyglycol ethers are suitablestructurants.

Of the clays, particularly preferred are synthetic hectorite (laponite)clay used in conjunction with an electrolyte salt capable of causing theclay to thicken. Suitable electrolytes include alkali and alkaline earthsalts such as halides, ammonium salts and sulphates.

The surface active agent phase may also comprise a thickening agent, iea material which maintains the viscosity of this phase as the shear ratethereof is increased during use. Suitable materials include cross-linkedpolyacrylates such as Carbopol™ (polymers available from Goodrich);natural gums including alginates, guar, xanthan and polysaccharidederivatives including carboxy methyl cellulose and hydroxypropyl guar;propylene glycols and propylene glycol oleates; salts such as sodiumchloride and ammonium sulphate; glycerol tallowates; and mixturesthereof.

Thickeners may also be added to the benefit agent in order to achievethe required viscosity during use. Preferred thickeners for the benefitagent include fumed silica; polyethylene; alkyl silicone waxes;aluminium silicate; lanesterol; natural and synthetic waxes; fatty acidsand derivatives thereof, in particular, fatty acid monoglyceridepolyglycol ethers; higher fatty alcohols; petrolatum; narogel;polyammonium stearate; hydrotalcites; and mixtures thereof.Hydrotalcites are materials of general formula

[M_(m)N_(n)(OH)_(2(m+n))]^(n+)X^(x−) _(n/x) .yH₂O

where M is a divalent metal ion e.g. Mg²⁻; N is a trivalent metal ione.g. Al²⁺; X is an exchangeable anion e.g CO₃ ⁻, NO₃ ⁻; stearate,cinnimate; m is the number of divalent metal ions; and n is the numberof trivalent metal ions.

Furthermore, the benefit agent may also function as a carrier to deliverefficacy agents to skin treated with the compositions of the invention.This route is particularly useful for delivering efficacy agents whichare difficult to deposit onto the skin or those which suffer detrimentalinteractions with other components in the composition. In such cases thecarrier is often a silicone or hydrocarbon oil which is nonsolubilised/micellised by the surface active phase and in which theefficacy agent is relatively soluble. Examples of such efficacy agentsinclude anti-viral agents; hydroxycaprylic acids; pyrrolidone;carboxylic acids; 3,4,4′-trichlorocarbanilide; benzoyl peroxide;perfumes; essential oils; germicides and insect repellants such as2,4,4′-trichloro-2′-hydroxydiphenyl ether (Irgasan DP300); salicylicacid; willow extract, N,N-dimethyl m-toluamide (DEET); and mixturesthereof.

The composition may contain one or more additional anionicsurface-active agents, in addition to the acyl sulphonate salt definedabove; preferably selected from salts of fatty acids; alkali metal saltsof mono- or dialkyl sulfates; mono- or dialkyl ether sulfates; laurylether sulfates; alkyl sulfonates; alkyl aryl sulfonates; primary alkanedisulfonates; alkene sulfonates; hydroxyalkane sulfonates; alkylglyceryl ether sulfonates; alpha-olefinsulfonates; alkyl phosphates;sulfonates of alkylphenolpolyglycol ethers; salts of alkylsulfopolycarboxylic acid esters; alkyl sulfosuccinates and saltsthereof, alkyl ether sulfosuccinates and salts thereof, non-acylatedalkyl isethionates; fatty acid taurates; acyl taurates; products ofcondensation of fatty acids with oxy- and aminoalkanesulfonic acids;sulfated derivatives of fatty acids and polyglycols; alkyl and acylsarcosinates; sulfoacetates; alkyl phosphates; alkyl phosphate esters;acyl lactates; alkanolamides of sulfated fatty acids and salts oflipoamino acids. Particularly exemplary salts of the above, whereapplicable, are the sodium, potassium, ammonium, magnesium andtriethylamine salts.

In the case of sodium lauryl ether sulfate, LESNa, this is asurface-active agent widely used in shampoos by reason of its foamingproperties. It is a cheap, conventional, washing base.

The composition may contain one or more non-ionic surface-active agents,preferably selected from the following: reaction products of compoundshaving a hydrophobic group and a reactive hydrogen atom, for examplealiphatic alcohols, acids, amides or alkyl phenols with alkylene oxides,especially ethylene oxide either alone or with propylene oxide (forexample alkyl (C₆-C₂₂) phenol-ethylene oxide condensates, thecondensation products of aliphatic (C₈-C₁₈) primary or secondary linearor branched alcohols with ethylene oxide, and products made bycondensation of ethylene oxide with the reaction products of propyleneoxide and ethylenediamine); long chain tertiary amine oxides, long chaintertiary phosphine oxides and dialkyl sulphoxides; alkyl amido amineoxides; alkyl tertiary phosphine oxides; alkoxyl alkyl amines; sorbitan;sorbitan esters; sucrose esters; sugar amides, such as a polysaccharideamide; lactobionamides; and alkyl polysaccharide nonionic surfactants,for example alkylpolyglycosides. Preferred non-ionic surfactants aresucroglycerides and ethyoxylated fatty alcohols, especially thosederived from lauryl, cetylstearyl, stearyl, cetyl and oleocetylalcohols.

A non-ionic surface active agent, when present, preferably comprises upto 15% wt of the composition, preferably up to 10% wt.

Representative solid particles include active materials or agents suchas those used for hair treatments, e.g., zinc pyrithione, or anyabrasive materials which may be of natural or synthetic origin. Inparticular, these are polycarbonates, polypropylenes, polyethylenes,alumina, calcite and clays. Such particles generally have a crystal sizeranging from about 1 to 600 microns and preferably from about 10 to 400microns.

In the case of the suspended droplets, these are preferably droplets ofat least one vegetable oil, essential oil and/or, more particularly,silicone oil.

The silicone oils which are well suited according to the presentinvention include the polyalkylsiloxanes, polyalkylarylsiloxanes andmixtures thereof. The preferred polyalkylsiloxanes are, especially,polydimethylsiloxanes such as dimethicone whose viscosity may range fromabout 20 mPa·s to 50 Pa·s at 25° C., pure or mixed with cyclomethicone.Particularly exemplary of the polyalkylarylsiloxanes are thepolyphenyldimethyl-siloxanes.

In particular, polydiorganosiloxanes such as polydimethylsiloxaneshaving a molecular weight of less than or equal to 3,000,000 andpolydimethyl-diphenylsiloxanes of molecular weight of about 600,000 areespecially well suited according to the invention. The size of the oildroplets within the compositions of the invention advantageously rangesfrom about 0.5 to 50 microns.

The formulations according to the invention may contain approximately0.5% to 8% and, preferably, about 1.5% to 4.5% by weight ofwater-insoluble particles.

Specific formulations of the invention may include these:

-   -   (a) as additional anionic agent LESNa and as co-surface-active        agent lauryl alcohol containing two moles of ethylene oxide per        mole of lauric alcohol and as electrolyte NaCl in a lauryl        alcohol 2EO/LESNa mole ratio of from 2.1 to 4.3,    -   (b) as additional anionic agent, a sodium lipoamino acid and the        lipoproteol LC0® mixed with the same lauryl alcohol containing        two moles of ethylene oxide per mole of lauric acid and having a        lauryl alcohol 2EO/sodium lipoamino acid mole ratio ranging from        about 1.2 to 6.7,    -   (c) as additional anionic agent LESNa, and as co-surface-active        agent oleylbetaine and as electrolyte NaCl, in an        oleylbetaine/LESNa mole ratio of from 1.1 to 3.7.

Generally, the compositions according to the invention contain ananionic surface-active agent mixed with at least one cosurface-activeagent in a cosurface-active agent/anionic surface-active agent moleratio equal to or greater than 1.

A benefit of the invention is the ability to suspend oil and/oremollient particles in a non-Newtonian composition. The followingoil/emollients may optionally be suspended in the compositions of theinvention. Various classes of oils are set forth below.

Vegetable oils: Arachis oil, castor oil, cocoa butter, coconut oil, cornoil, cotton seed oil, olive oil, palm kernel oil, rapeseed oil,safflower seed oil, sesame seed oil and soybean oil.

Esters: Butyl myristate, cetyl palmitate, decyloleate, glyceryl laurate,glyceryl ricinoleate, glyceryl stearate, glyceryl isostearate, hexyllaurate, isobutyl palmitate, isocetyl stearate, isopropyl isostearate,isopropyl laurate, isopropyl linoleate, isopropyl myristate, isopropylpalmitate, isopropyl stearate, propylene glycol monolaurate, propyleneglycol ricinoleate, propylene glycol stearate, and propylene glycolisostearate.

Animal Fats: acetylated lanolin alcohols, lanolin, lard, mink oil andtallow.

Other examples of oil/emollients include mineral oil, petrolatum,silicone oil such as dimethyl polysiloxane, lauryl and myristyl lactate.

The emollient/oil is generally used in an amount from about 0 to 20%,preferably 0 to 15% by wt. of the composition.

In addition, the compositions of the invention may include optionalingredients as follows:

-   -   Organic solvents, such as ethanol; auxiliary thickeners,        sequestering agents, such as tetrasodium        ethylenediaminetetraacetate (EDTA), EHDP or mixtures in an        amount of 0.01 to 1%, preferably 0.01 to 0.05%; and coloring        agents, opacifiers and pearlizers such as zinc stearate,        magnesium stearate, TiO₂, EGMS (ethylene glycol monostearate) or        Lytron 621 (Styrene/Acrylate copolymer); all of which are useful        in enhancing the appearance or cosmetic properties of the        product.    -   Antimicrobials such as 2-hydroxy-4,2′4′ trichloro-diphenyl-ether        (DP300); preservatives, for example dimethyloldimethyl-hydantoin        (Glydant XL1000), parabens, sorbic acid etc.    -   Coconut acyl mono- or diethanol amides as suds boosters, and        strongly ionizing salts such as sodium chloride and sodium        sulfate may also be used to advantage.    -   Antioxidants such as, for example, butylated hydroxytoluene        (BHT) may be used advantageously in amounts of about 0.01% or        higher if appropriate.    -   Cationic conditioners which may be used include Quatrisoft        LM-200 Polyquaternium-24, Merquat Plus 3330-Polyquaternium 39;        Jellner Polyquaternium 10; Merquat 550; and Jaguar® type        conditioners.    -   Deflocculating polymers.    -   Chelating agents including but not limited to EDTA, EDTA salts,        NTA, methylenediamine disuccinate and salts of methylenediamine        disucuccinate.

Compositions of the invention may be formulated as products for washingthe skin, for example, bath or shower gels, hand washing compositions orfacial washing liquids; pre- and post-shaving products; rinse-off,wipe-off and leave-on skin care products; products for washing the hairand for dental use.

In accordance with a second aspect of the present invention there isprovided the use of a composition of the invention, as defined above, inthe formulation of a personal care product with improved stability, inan aqueous environment.

In accordance with a third aspect of the present invention there isprovided the use of a composition of the invention, as defined above, inthe formulation of a personal care product which has improved stabilityin an aqueous environment compared with a corresponding compound inwhich each of R² to R⁵ is a hydrogen atom.

Suitably the composition, and in particular the defined sulfonatedcompound, is resistant to breakdown in an aqueous environment.Preferably it has essentially no effect on the pH of the product, overtime. It has excellent lathering properties and is very mild to skin andeyes.

Weight percentage values herein refer to the total complement ofcompounds of a named type, e.g. amphoteric or zwitterionic surfactantsin total; or benefit agents in total.

Where a percentage value is given for a component it refers to theactive content of that component.

The invention will now be further described, by way of example, withreference to the following examples.

Examples 1 to 5 were carried out to assess the suitability of certainisethionate salts for use in the present invention. Examples 6-14 relateto certain compositions which are within the scope of the presentinvention.

In the examples abbreviations used are as follows:

SCMI—sodium cocoylmethylisethionateSCI—sodium cocoyl isethionateSLS—sodium lauryl sulfateSLMI—sodium lauroylmethylisethionateSLES—sodium laureth sulfateSCEI—sodium cocoyl ethyl isethionateCAPB—cocamidopropyl betaineCMEA—cocamide monoethanolamine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plot showing the amount of sodium cocoylmethylisethionate(SCMI) present in aqueous solutions having various pH values followingincubation at 48.9° C. at various intervals over a 30 day period oftime.

FIG. 2 is a plot showing the pH stability of sodiumcocoylmethylisethionate (SCMI) present in aqueous solutions havingvarious pH values following incubation at 48.9° C. at various intervalsover a 30 day period of time.

FIG. 3 is a plot showing skin irritancy properties of a number ofcompounds, including two sulfate surfactants; SLS and SLES (known tohave significant irritancy), distilled water, SCI (known to have lowirritancy), and SCMI, as described in Example 3.

EXAMPLE 1

In a preliminary test the stability of SCMI in 10 wt % aqueous solutionsadjusted to have initial pH values respectively of 4.5, 5.5, 6.5, 7.5,8.5 and 9.5, each held at 48.9° C. for an extended period of days, weretested for the amount of SCMI present over the test period.

The pH values were read using a standard electrode pH meter (FisherAccument XL-25). The electrode was place in the composition (no furtherdilution) and the pH recorded.

The results are shown in FIG. 1. It can be seen that the percentage ofSCMI does not change from Day 0 to Day 30, at any of these pH values.

EXAMPLE 2

In a preliminary test 10 wt % solutions of SCMI, adjusted to haveinitial pH values respectively of 4.5, 5.5, 6.5, 7.5, 8.5 and 9.5, eachheld at 48.9° C. for an extended period of days, were tested for theirpH stability over the extended period. The pH testing was as describedabove.

The results are shown in FIG. 2. It can be seen that the pH values weresubstantially unchanged from Day 0 to Day 30 at all these pH values,except for a small pH reduction in the first few days, for the sampleheld at the highest pH value, 9.5.

EXAMPLE 3

In a preliminary test based on the Zein protocol the skin irritancyproperties of a number of compounds were tested, including two sulfatesurfactants SLS and SLES (known to have significant irritancy),distilled water, SCI (known to have low irritancy) and SCMI. The resultsare shown in FIG. 3. SCMI and SLMI were shown to have low irritancy,similar to that shown by SCI; and significantly lower than the sulfates.

The Zein protocol is an in-vitro test to measure skin irritancy offormulations. The method makes use of the correlation between bindingability of surfactants to proteins and the damage the surfactant causesto the skin. The de-naturation of epidermal protein is a key mechanismin the development of observable damage to the skin by surfactants. Zeinprotein, an insoluble protein extracted from corn kernel, is used as amodel for epidermal protein and the solubility of the Zein protein insurfactant solutions is believed to be a reliable guide for the skinirritancy caused by the surfactant. The test involves establishing theamount of Zein protein which can be solubilised by surfactant. 5 g ofZein protein may be dispersed in 40 cm³ of surfactant solution (at 2 wt% concentration). The mixture is shaken for 1 hour at 35° C., andimmediately centrifuged to remove any non-solubilised Zein. The amountsolubilised is estimated from the solution nitrogen content usingmicro-Kjeldahl method (making allowance for any nitrogen in the compoundtested).

EXAMPLE 4

Simple solubility tests were carried out.

10 wt % of SCI shaken with deionised water gave a milky whitesuspension. The solubility limit of SCI in water is quoted as 0.5 wt %.10 wt % of SCMI added to deionised water immediately gave a clearsolution.10 wt % of SCEI added to deionised water immediately gave a clearsolution.

EXAMPLE 5

Foaming tests were performed using a capped measuring cylinder which wascharged with an aliquot of the stated surfactant leaving room for foamto form. Foam heights in the graduated cylinder were measured at thestart and after 10 inversions of the cylinder. The operation was carriedout in the same manner for each surfactant.

100% SLES gave a foam of medium height but which was also open and“watery”.

80 wt % SLS/20 wt % CAPB gave a foam which was high but open and“watery”.

100% SCMI gave a foam of medium height but which was rich and creamy.

80% SCMI/20% CAPB gave a foam of medium height but which was rich andcreamy.

EXAMPLES 6 TO 14

Formulated compositions containing canola oil as benefit agent wereprepared and tested for viscosity and physical stability over aone-month period. The results are set out in the table below.

Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Ex. 14 Water 51.650.6 49.6 48.6 66.66 49.6 49.6 45.35 42.85 NTRLQUEST E- 1 1 1 1 1 1 30(formerly OCTAQUEST E- 30) Tetrasodium 0.25 0.25 EDTA (40%) FINSOFT C-170.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Cocamidopropyl 12.5 16.67 12.5 12.5 12.512.5 betaine (30%) Sodium 12.5 12.5 12.5 5 7.5 Lauroamphoacetate SCMI(85%) 15 15 15 15 6.17 15 SLMI (85%) 15 15 15 Cocamide MEA 3.5 3.5 3.53.5 3.5 3.5 3.5 3.5 Canola oil 12 12 12 12 2.5 12 12 12 12 Sodiumchloride 3 4 5 6 8 5 5 5 5 50% citric acid 1 1 1 1 1 1 1 1 solution (topH 5-6) NTRLQUEST, OCTAQUEST, FINSOFT are registered trade marks ofInnospec Brookfield RVT Viscometer Heleopath T-Bar Spindles @ 25° C.T-Bar Spindle B @ 14,800 18,000 27200 37200 1 RPM T-Bar Spindle B @ 83209600 13,760 18400 2.5 RPM T-Bar Spindle C @ 17000 60000 56000 7700077000 1 RPM T-Bar Spindle C @ 20400 28400 28000 37200 36400 2.5 RPMAppearance White White White White White White White White White LotionLotion Lotion Lotion Lotion Lotion Lotion Lotion Lotion Stability over 1Stable Stable Stable Stable Stable Stable Stable Stable Stable monthtest period

The formulations of Examples 15 and 16 were prepared by progressivemixing and blending of the components, in the order given. The pH wasadjusted to between 5.2 and 5.8 using citric acid after blending of thepreceding components (in the respective tables), but before blending inof the fragrance, dye and preservative.

EXAMPLE 15

The following moisturizing and conditioning shampoo was prepared.

Tradename Ingredients (Supplier) % w/w Water to 100 TrisodiumEthylenediamine Natrlquest E30 0.15 disuccinate (Innospec) SodiumChloride 4.00 Guar Hydroxypropyltrimonium Activsoft C-17 0.2 Chloride(Innospec) Disodium Miranol C2M Conc. 7.5 Cocoamphodipropionate (Rhodia)Sodium Methyl Cocoyl Pureact WS Conc. 7.5 Taurate (Innospec) Guar GumActivsoft S (Innospec) 0.5 Glycerin 1.00 SLMI Pureact SLMI-85 12.5(Innospec) Cocamide MEA Aminol CM Flakes 3.5 (Innospec) Quaternium 75Condicare CT (Innospec) 2.00 Dimethicone Dow Corning 200 Fluid 4.00 (DowCorning) Cocamidopropyl Betaine Mirataine BET C-30 10.00 (Rhodia) CitricAcid (50% soln) pH 5.2-5.8 Preservative trace Fragrance trace Dye(s)trace

The viscosity of the conditioning shampoo of Example 15 was tested underdifferent shear rates, on a viscometer with a T-Bar C Spindle, at 22° C.The results were as follows:

-   -   0.5 RPM=160,000 cps    -   1.0 RPM=90,000 cps    -   2.5 RPM=42,400 cps

EXAMPLE 16

The following foaming body lotion was prepared.

Ingredients Tradename (Supplier) % w/w to 100 Water to 100 TrisodiumEthylenediamine Natrlquest E30 0.15 disuccinate (Innospec) SodiumChloride 3.6 Guar Hydroxypropyltrimonium Activsoft C-17 0.18 Chloride(Innospec) Disodium Miranol C2M Conc. 6.7 Cocoamphodipropionate (Rhodia)Sodium Methyl Cocoyl Pureact WS Conc. 6.7 Taurate (Innospec) Guar GumActivsoft S (Innospec) 0.45 Glycerin 1.00 SLMI Pureact SLMI-85 11.2(Innospec) Cocamide MEA Aminol CM Flakes 3.1 (Innospec) Canola Oil RitaCanola Oil (Rita) 9.00 Cocamidopropyl Betaine Mirataine BET C-30 10.00(Rhodia) Trideceth-7 Carboxylic Pureact TA (Innospec) 3.5 Acid CitricAcid (50% soln) to pH 5.2-5.8 Preservative trace Fragrance trace Dye(s)trace

The viscosity of the foaming body lotion of Example 16 was tested underdifferent shear rates, on a viscometer with a T-Bar C Spindle, at 22° C.The results were as follows:

-   -   0.5 RPM=240,000 cps    -   1.0 RPM=140,000 cps    -   2.5 RPM=64,000 cps

1-14. (canceled)
 15. An aqueous personal care composition comprising: a)at least 3 wt % of a sulfonate compound of the general formula:

where R₁ represents a C₈₋₂₂ alkyl group; R₂ represents a C₁₋₄ alkylgroup; and each of R₃, R₄ and R₅ independently represents a hydrogenatom or a C₁₋₄ alkyl group, and M⁺ represents a cation; b) at least 3 wt% of an amphoteric or zwitterionic surfactant; c) at least 10 wt % ofwater; d) at least 0.5 wt % of an additional component in the form ofwater-insoluble solid or non-solid particles or droplets suspended inthe composition; and e) an electrolyte present in an amount from 2 wt %to 25 wt %; wherein said composition maintains said water-insolublesolid or non-solid particles or droplets suspended in the compositionwithout sedimentation or separation over a time period of at least onemonth, and wherein the composition is shear-thinning in the absence ofan additional structurant.
 16. The composition as claimed in claim 15wherein R₂ represents a methyl group.
 17. The composition as claimed inclaim 15 wherein each of R₃, R₄ and R₅ represents a hydrogen atom. 18.The composition as claimed in claim 16 wherein each of R₃, R₄ and R₅represents a hydrogen atom.
 19. The composition as claimed in claim 15wherein component (a) is present in an amount of up to 30 wt %.
 20. Thecomposition as claimed in claim 15 wherein component (b) is present inan amount of up to 30 wt %.
 21. The composition as claimed in claim 15wherein component (c) is present in an amount of from 20% to 95% bytotal composition weight.
 22. The composition as claimed in claim 15wherein component (d) is present in an amount from at least 0.5 wt %.23. The composition as claimed in claim 15, formulated as a productselected from the following: a bath or shower gel; a hand washingcomposition; a facial washing composition; a pre-, during- orpost-shaving product; a skin moisturizer; a hair gel; a medicinal skintreatment product; a shampoo; a hair conditioner; a dental product. 24.The composition as claimed in claim 15, wherein said electrolyte ispresent in an amount up to 15 wt %.
 25. The composition as claimed inclaim 15, wherein said electrolyte is present in an amount up to 10 wt%.
 26. The composition as claimed in claim 15 comprising a benefitagent.
 27. An aqueous personal care composition comprising: (a) a shearthinning composition, consisting of: i) at least 3 wt % of a sulfonatecompound of the general formula:

where R₁ represents a C₈₋₂₂ alkyl group; R₂ represents a C₁₋₄ alkylgroup; and each of R₃, R₄ and R₅ independently represents a hydrogenatom or a C₁₋₄ alkyl group, and M⁺ represents a cation; ii) anelectrolyte present in an amount from 2 wt % to 25 wt %; iii) at least 3wt % of an amphoteric or zwitterionic surfactant; and iv) at least 10 wt% of water; and (b) at least 0.5 wt % of an additional component in theform of water-insoluble solid or non-solid particles or dropletssuspended in the composition; wherein said composition maintains saidwater-insoluble solid or non-solid particles or droplets suspended inthe composition without sedimentation or separation over a time periodof at least one month.
 28. The composition as claimed in claim 27wherein R₂ represents a methyl group.
 29. The composition as claimed inclaim 27 wherein each of R₃, R₄ and R₅ represents a hydrogen atom. 30)The composition as claimed in claim 28 wherein each of R₃, R₄ and R₅represents a hydrogen atom.
 31. The composition as claimed in claim 27comprising a benefit agent.